Umbrella eBay account in own clasifieds portal

Is it possible to have an umbrella accounts on eBay? How it technically works? Please share with any experiences. Thank you in advance. Here some tasks: 1. Traders registering on my clasifieds portal automatically creates an Account on eBay under cover by my "umbrella account" with all functions as if it will be done directly on eBay. How it works? 2. How many accounts could be covered by my "umbrella"? 3. Does it possible to cover by "umbrella account" the traders, users, buyers accounts? It comes from owned clasifieds portal. 4. How it could be combined with an afliate program? 5. If the Accounts will connects directly to eBay, they will find their profile and listings? 6. Does they still have be covered by umbrella Account? 7. Does the same covered Accounts clasifieds Listings will apear aslo on eBay? I believe yes, but I asking to check it. 8. Does it possible to convert existing clasifieds portal Accounts to eBay pre-accounts? 9. Please share with your know completed portal examples. 10. Post by everslaweb@gmail.com